Showing papers on "Atmospheric carbon cycle published in 2007"

Contributions to accelerating atmospheric CO2 growth from economic activity, carbon intensity, and efficiency of natural sinks

Abstract: The growth rate of atmospheric carbon dioxide (CO2), the largest human contributor to human-induced climate change, is increasing rapidly. Three processes contribute to this rapid increase. Two of these processes concern emissions. Recent growth of the world economy combined with an increase in its carbon intensity have led to rapid growth in fossil fuel CO2 emissions since 2000: comparing the 1990s with 2000 –2006, the emissions growth rate increased from 1.3% to 3.3% y 1 . The third process is indicated by increasing evidence (P 0.89) for a long-term (50-year) increase in the airborne fraction (AF) of CO2 emissions, implying a decline in the efficiency of CO2 sinks on land and oceans in absorbing anthropogenic emissions. Since 2000, the contributions of these three factors to the increase in the atmospheric CO2 growth rate have been65 16% from increasing global economic activity, 17 6% from the increasing carbon intensity of the global economy, and 18 15% from the increase in AF. An increasing AF is consistent with results of climate– carbon cycle models, but the magnitude of the observed signal appears larger than that estimated by models. All of these changes characterize a carbon cycle that is generating stronger-than-expected and sooner-than-expected climate forcing. airborne fraction anthropogenic carbon emissions carbon‐climate feedback terrestrial and ocean carbon emissions vulnerabilities of the carbon cycle

CO2 balance of boreal, temperate, and tropical forests derived from a global database

Abstract: Terrestrial ecosystems sequester 2.1 Pg of atmospheric carbon annually. A large amount of the terrestrial sink is realized by forests. However, considerable uncertainties remain regarding the fate of this carbon over both short and long timescales. Relevant data to address these uncertainties are being collected at many sites around the world, but syntheses of these data are still sparse. To facilitate future synthesis activities, we have assembled a comprehensive global database for forest ecosystems, which includes carbon budget variables (fluxes and stocks), ecosystem traits (e.g. leaf area index, age), as well as ancillary site information such as management regime, climate, and soil characteristics. This publicly available database can be used to quantify global, regional or biome-specific carbon budgets; to re-examine established relationships; to test emerging hypotheses about ecosystem functioning [e.g. a constant net ecosystem production (NEP) to gross primary production (GPP) ratio]; and as benchmarks for model evaluations. In this paper, we present the first analysis of this database. We discuss the climatic influences on GPP, net primary production (NPP) and NEP and present the CO2 balances for boreal, temperate, and tropical forest biomes based on micrometeorological, ecophysiological, and biometric flux and inventory estimates. Globally, GPP of forests benefited from higher temperatures and precipitation whereas NPP saturated above either a threshold of 1500 mm precipitation or a mean annual temperature of 10 degrees C. The global pattern in NEP was insensitive to climate and is hypothesized to be mainly determined by nonclimatic conditions such as successional stage, management, site history, and site disturbance. In all biomes, closing the CO2 balance required the introduction of substantial biome-specific closure terms. Nonclosure was taken as an indication that respiratory processes, advection, and non-CO2 carbon fluxes are not presently being adequately accounted for.

The impact of agricultural soil erosion on the global carbon cycle

Abstract: Agricultural soil erosion is thought to perturb the global carbon cycle, but estimates of its effect range from a source of 1 petagram per year(-1) to a sink of the same magnitude. By using caesium-137 and carbon inventory measurements from a large-scale survey, we found consistent evidence for an erosion-induced sink of atmospheric carbon equivalent to approximately 26% of the carbon transported by erosion. Based on this relationship, we estimated a global carbon sink of 0.12 (range 0.06 to 0.27) petagrams of carbon per year(-1) resulting from erosion in the world's agricultural landscapes. Our analysis directly challenges the view that agricultural erosion represents an important source or sink for atmospheric CO2.

Black carbon sequestration as an alternative to bioenergy

Abstract: Most policy and much research concerning the application of biomass to reduce global warming gas emissions has concentrated either on increasing the Earth’s reservoir of biomass or on substituting biomass for fossil fuels, with or without CO2 sequestration. Suggested approaches entail varied risks of impermanence, delay, high costs, and unknowable side-effects. An under-researched alternative approach is to extract from biomass black (elemental) carbon, which can be permanently sequestered as mineral geomass and may be relatively advantageous in terms of those risks. This paper reviews salient features of black carbon sequestration and uses a high-level quantitative model to compare the approach with the alternative use of biomass to displace fossil fuels. Black carbon has been demonstrated to produce significant benefits when sequestered in agricultural soil, apparently without bad side-effects. Black carbon sequestration appears to be more efficient in general than energy generation, in terms of atmospheric carbon saved per unit of biomass; an exception is where biomass can efficiently displace coal-fired generation. Black carbon sequestration can reasonably be expected to be relatively quick and cheap to apply due to its short value chain and known technology. However, the model is sensitive to several input variables, whose values depend heavily on local conditions. Because characteristics of black carbon sequestration are only known from limited geographical contexts, its worldwide potential will not be known without multiple streams of research, replicated in other contexts.

The first state of the carbon cycle report (SOCCR): The North American carbon budget and implications for the global carbon cycle.

Abstract: North America is currently a net source of CO2 to the atmosphere, contributing to the global buildup of greenhouse gases in the atmosphere and associated changes in the Earth’s climate. In 2003, North America emitted nearly two billion metric tons of carbon to the atmosphere as CO2. North America’s fossil-fuel emissions in 2003 (1856 million metric tons of carbon ±10% with 95% certainty) were 27% of global emissions. Approximately 85% of those emissions were from the United States, 9% from Canada, and 6% from Mexico. The combustion of fossil fuels for commercial energy (primarily electricity) is the single largest contributor, accounting for approximately 42% of North American fossil emissions in 2003. Transportation is the second largest, accounting for 31% of total emissions. There are also globally important carbon sinks in North America. In 2003, growing vegetation in North America removed approximately 500 million tons of carbon per year (±50%) from the atmosphere and stored it as plant material and soil organic matter. This land sink is equivalent to approximately 30% of the fossil-fuel emissions from North America. The imbalance between the fossil-fuel source and the sink on land is a net release to the atmosphere of 1350 million metric tons of carbon per year (± 25%). Approximately 50% of North America’s terrestrial sink is due to the regrowth of forests in the United States on former agricultural land that was last cultivated decades ago, and on timberland recovering from harvest. Other sinks are relatively small and not well quantified with uncertainties of 100% or more. The future of the North American terrestrial sink is also highly uncertain. The contribution of forest regrowth is expected to decline as the maturing forests grow more slowly and take up less CO2 from the atmosphere. But this expectation is surrounded by uncertainty because how regrowing forests and other sinks will respond to changes in climate and CO2 concentration in the atmosphere is highly uncertain. The large difference between current sources and sinks and the expectation that the difference could become larger if the growth of fossil-fuel emissions continues and land sinks decline suggest that addressing imbalances in the North American carbon budget will likely require actions focused on reducing fossil-fuel emissions. Options to enhance sinks (growing forests or sequestering carbon in agricultural soils) can contribute, but enhancing sinks alone is likely insufficient to deal with either the current or future imbalance. Options to reduce emissions include efficiency improvement, fuel switching, and technologies such as carbon capture and geological storage. Implementing these options will likely require an array of policy instruments at local, regional, national, and international levels, ranging from the encouragement of voluntary actions to economic incentives, tradable emissions permits, and regulations. Meeting the demand for information by decision makers will likely require new modes of research characterized by close collaboration between scientists and carbon management stakeholders. The U.S. Climate Change Science Program Executive Summary 2 3 ES.1 SyNTHES S AND ASSESSMENT OF THE NORTH AMER CAN CARBON BUDGET Understanding the North American carbon budget, both sources and sinks, is critical to the United States Climate Change Science Program goal of providing the best possible scientific information to support public discussion, as well as government and private sector decision making, on key climate-related issues. In response, this report provides a synthesis, integration, and assessment of the current knowledge of the North American carbon budget and its context within the global carbon cycle. The report focuses on the carbon cycle as it influences the concentration of carbon dioxide (CO2) in the atmosphere. Methane (CH4), nitrous oxide, and other greenhouse gases are also relevant to climate issues, but their consideration is beyond the scope and mandate of this report. The report is organized as a response to questions relevant to carbon management and to a broad range of stakeholders charged with understanding and managing energy and land use. The questions were identified through early and continuing dialogue with these stakeholders, including scientists; decision makers in the public and private sectors, including national and sub-national government; carbon-related industries, such as energy, transportation, agriculture, and forestry; and climate policy and carbon management interest groups. The questions and the answers provided by this report are summarized below. The reader is referred to the indicated chapters for further, more detailed, discussion. Unless otherwise referenced, all values, statements of findings and conclusions are taken from the chapters of this report where the attribution and citation of the primary sources can be found. ES.2 WHAT S THE CARBON CyCLE AND WHy SHOULD WE CARE? The carbon cycle, described in Chapters 1 and 2, is the combination of many different physical, chemical, and biological processes that transfer carbon between the major storage pools (known as reservoirs): the atmosphere, plants, soils, freshwater systems, oceans, and geological sediments. Hundreds of millions of years ago, and over millions of years, this carbon cycle was responsible for the formation of coal, petroleum, and natural gas, the fossil fuels that are the primary sources of energy for our modern societies. Humans have altered the Earth’s carbon budget. Today, the cycling of carbon among atmosphere, land, and freshwater and marine environments is in rapid transition and out of balance. Over tens of years, the combustion of fossil fuels is releasing into the atmosphere quantities of carbon that were accumulated in the Earth system over millions of years. Furthermore, tropical forests that once held large quantities of carbon are being converted to agricultural lands, releasing additional carbon to the atmosphere as a result. Both the fossil-fuel and land-use related releases are sources of carbon to the atmosphere. The combined rate of release is far larger than can be balanced by the biological and geological processes that naturally remove CO2 from the atmosphere and store it in terrestrial and marine environments as part of the Earth’s carbon cycle. These processes are known as sinks. Therefore, much of the CO2 released through human activity has “piled up” in the atmosphere, resulting in a dramatic increase in the atmospheric concentration of CO2. The concentration increased by 31% between 1850 and 2003, and the present concentration is higher than at any time in the past 420,000 years. Because CO2 is an important greenhouse gas, the imbalance between sources and sinks and the subsequent increase in concentration in the atmosphere is very likely causing changes in Earth’s climate (IPCC, 2007). Furthermore, these trends in fossil-fuel use and tropical deforestation are accelerating. The magnitude of the changes raises concerns about the future behavior of the carbon cycle. Will the carbon cycle continue to function as it has in recent history, or will a CO2-caused warming result in a weakening of the ability of sinks to take up CO2, leading to further warming? Drought, for example, may reduce forest growth. Warming can release carbon stored in soil, and warming and drought may increase forest fires. Conversely, will elevated concentrations of CO2 in the atmosphere stimulate plant growth as it is known to do in laboratory and field experiments and thus strengthen global or regional sinks? The question is complicated because CO2 is not the only substance in the atmosphere that affects the Earth’s surface temperature and climate. Other greenhouse gases include CH4, nitrous oxide, the halocarbons, and ozone, and all of these gases, together with water vapor, aerosols, solar radiation, and properties of the Earth’s surface, are involved in the evolution of climate change. Carbon dioxide, alone, is responsible for approximately 55-60% of the change in the Earth’s radiation balance due to increases in well-mixed atmospheric greenhouse gases and CH4 for about another 20% (values are for the late 1990s; with a relative uncertainty of The rate of CO2 released to the atmosphere is far larger than can be balanced by the biological and geological processes that naturally remove CO2 from the atmosphere and store it in terrestrial and marine environments. Trends in fossil-fuel use and tropical deforestation

12 – carbon cycling and formation of soil organic matter

Abstract: Publisher Summary This chapter discusses carbon (C) cycling and formation of soil organic matter. C was deposited on earth from carbonaceous comets and asteroids in both organic and inorganic forms. The extraterrestrial C contained complex compounds including hydrocarbons, organic acids, and amino compounds essential to the evolution of cellular life forms. The “Carbon cycle” is the transfer of C among the atmosphere, oceans, land, and life. The C cycle is composed of both long-term and short-term cycles. The short-term C cycle is dominated by the interplay of terrestrial and marine photosynthesis, respiration, and organic matter formation. The short-term C cycle is dependent on two principle gases: CO2 and methane (CH4). Perturbations of the short-term C cycle causing changes in the concentration of these two gases in the atmosphere cause potential changes in climate because both are greenhouse gases. The chapter describes the long-term carbon cycle, short-term C cycle, and ecosystem C cycling in detail. The composition and turnover of C inputs to soil is explained along with soil organic matter and role of methane in the C cycle.

Call Off the Quest

Abstract: Knowledge of the long-term response of Earth's climate to a doubling of atmospheric carbon doixide may be less useful for policy-makers than commonly assumed.

Carbon cycle: marine manipulations.

Abstract: The effect of increasing levels of atmospheric carbon dioxide on carbon uptake in and export from the upper ocean is one of the big questions in environmental science. But it can be tackled experimentally.

Spatial Distribution and Temporal Change of Carbon Storage in Timber Biomass of Two Different Forest Management Units

Abstract: Forests make up large ecosystems and can play an important role in mitigating the emissions of CO2, the most important greenhouse gas. However, they are sources of atmospheric carbon when they are disturbed by human or natural causes. Storage of carbon through expansion and adaptive management of forest ecosystems can assist in reducing carbon concentrations in atmosphere. This study proposes a methodology to produce spatially explicit estimates of the carbon storages (aboveground plus belowground) depending on land use/cover changes in two different forest ecosystems during various periods. Carbon storages for each forest ecosystem were projected according to inventory data, and carbon storages were mapped in a geographic information system (GIS). Results showed that total carbon stored in above and belowground of both forest ecosystems increased from one period to other because of especially increase of productive forest areas and decline of degraded forest areas as well as protection of spruce forests subject to insect attacks.

Carbon Dioxide Emissions and Carbonation Sensors

Abstract: The gases with higher heat capacities than those of O2 and N2 cause greenhouse effects. Carbon dioxide (CO2) is the main greenhouse gas associated with global climate change. At the present time, coal is responsible for 30–40% of world CO2 emissions from fossil fuels. There was a higher correlation between the amount of carbon dioxide emission and percentage of carbon in the fuel for all equations. The squares of correlation coefficients were 0.9999, 0.9978, and 0.9995. The gas sensing characteristics of MgO and CaO as the CO2 gas sensors and CO2 emission capacities selected carbonaceous fuels have been investigated. It was found that increasing the percentage of carbon in carbonaceous fuel caused CO2 emission increase. Carbonation is a stabilization of CO2 by solidification process. The availability of a CO2 fixation technology would serve as insurance in case global warming causes severe restrictions on CO2 emissions. In order to prevent rapid climate change, it will be necessary to stabilize C...

Carbon dioxide concentration in Mediterranean greenhouses: how much lost production?

Abstract: In the absence of artificial supply of carbon dioxide in the greenhouse environment, the CO2 absorbed in the process of photosynthesis must ultimately come from the external ambient through the ventilation openings. This requires that the CO2 concentration within the house must be lower than the external concentration, as there would be no flow inwards otherwise. Since potential assimilation (that is, the assimilation level that can be attained when no other factor is limiting) is heavily dependent on carbon dioxide concentration, this implies that assimilation is reduced, whatever the light level or crop status. The ventilation of the greenhouse implies a trade-off between ensuring inflow of carbon dioxide and maintaining an adequate temperature within the house, particularly during sunny, chilly days. We apply a simple model, on which the Dutch ?philosophy? of CO2 fertilisation is based, for estimating the potential production loss, through data measured in commercial greenhouses in Almeria and Sicily. Thereafter we discuss the management options for a grower to limit losses. In particular we analyse costs, potential benefits and consequences of bringing in more carbon dioxide either through increased ventilation, at the cost of lowering temperature, or through artificial supply. We find out that, whereas the reduction in production caused by depletion is comparable to the reduction resulting from the lower temperature caused by ventilation to avoid depletion, compensating the effect of depletion is much cheaper than making up the loss by heating.

Climate and carbon cycle variations in the 20th and 21st centuries in a model of intermediate complexity

Abstract: The climate model of intermediate complexity developed at the Oboukhov Institute of Atmospheric Physics, Russian Academy of Sciences (IAP RAS CM), has been supplemented by a zero-dimensional carbon cycle model. With the carbon dioxide emissions prescribed for the second half of the 19th century and for the 20th century, the model satisfactorily reproduces characteristics of the carbon cycle over this period. However, with continued anthropogenic CO2 emissions (SRES scenarios A1B, A2, B1, and B2), the climate-carbon cycle feedback in the model leads to an additional atmospheric CO2 increase (in comparison with the case where the influence of climate changes on the carbon exchange between the atmosphere and the underlying surface is disregarded). This additional increase is varied in the range 67–90 ppmv depending on the scenario and is mainly due to the dynamics of soil carbon storage. The climate-carbon cycle feedback parameter varies nonmonotonically with time. Positions of its extremes separate characteristic periods of the change in the intensity of anthropogenic emissions and of climate variations. By the end of the 21st century, depending on the emission scenario, the carbon dioxide concentration is expected to increase to 615–875 ppmv and the global temperature will rise by 2.4–3.4 K relative to the preindustrial value. In the 20th–21st centuries, a general growth of the buildup of carbon dioxide in the atmosphere and ocean and its reduction in terrestrial ecosystems can be expected. In general, by the end of the 21st century, the more aggressive emission scenarios are characterized by a smaller climate-carbon cycle feedback parameter, a lower sensitivity of climate to a single increase in the atmospheric concentration of carbon dioxide, a larger fraction of anthropogenic emissions stored in the atmosphere and the ocean, and a smaller fraction of emissions in terrestrial ecosystems.

Implications of changing from grazed or semi-natural vegetation to forestry for carbon stores and fluxes in upland organo-mineral soils in the UK

Abstract: In the UK, as organo-mineral soils are a significant store of soil organic carbon (SOC), they may become increasingly favoured for the expansion of upland forestry. It is important, therefore, to assess the likely impacts on SOC of this potentially major land use change. Currently, these assessments rely on modelling approaches which assume that afforestation of organo-mineral soils is "carbon neutral". This review evaluates this assumption in two ways. Firstly, UK information from the direct measurement of SOC change following afforestation is examined in the context of international studies. Secondly, UK data on the magnitude and direction of the major fluxes in the carbon cycle of semi-natural upland ecosystems are assessed to identify the likely responses of the fluxes to afforestation of organo-mineral soils. There are few directly relevant measurements of SOC change following afforestation of organo-mineral soils in the UK uplands but there are related studies on peat lands and agricultural soils. Overall, information on the magnitude and direction of change in SOC with afforestation is inconclusive. Data on the accumulation of litter beneath conifer stands have been identified but the extent to which the carbon held in this pool is incorporated into the stable soil carbon reservoir is uncertain. The effect of afforestation on most carbon fluxes is small because the fluxes are either relatively minor or of the same magnitude and direction irrespective of land use. Compared with undisturbed moorland, particulate organic carbon losses increase throughout the forest cycle but the data are exclusively from plantation conifer forests and in many cases pre-date current industry best practice guidelines which aim to reduce such losses. The biggest uncertainty in flux estimates is the relative magnitude of the sink for atmospheric carbon as trees grow and mature compared with that lost during site preparation and harvesting. Given the size of this flux relative to many of the others, this should be a focus for future carbon research on these systems.

Mining methane, sequestering carbon dioxide and farming in oceans

Abstract: The present invention is a multiple purposed system of producing methane from its hydrates and sequestering carbon dioxide into its hydrates. Methane hydrates mixed with mud, prepared with methane mining assembly 23 are brought to sea surface by a series of buckets 16 attaching to rotating chains 18 . The decomposed methane is collected into the methane dome 50 and is processed into liquefied natural gas or synthetic liquid fuels. Liquid carbon dioxide is brought down through a tube 70 and a sequestering device 86 into the sea where the pressure and the temperature are adequate for carbon dioxide hydrates to form and settle down to the sea bottom. The unconverted gaseous carbon dioxide is collected into carbon dioxide dome 49 and is liquefied again for recycling. A specially designed marine plantation, comprising of plurality of planting units 352 and a fleet of seeding and harvesting boats, is employed to remove the residual carbon dioxide from the sequestering, to alleviate the global warming, to serves as an abundant source of renewable energy, and as a huge sink for carbon. In addition, it could provide a profusion of less-polluted seafood. The operations of mining methane, sequestering carbon dioxide and marine plantation are fully integrated and optimized

The Terra Preta phenomenon

Abstract: The greatest legacy the Amazonians left to the World was not the famed ‘City of Gold’ but the Terra Preta. These man-made ‘Indian black earths’ cover an area the size of France. They hold a secret to carbon sequestration that could reduce carbon dioxide emissions and global warming. We require only 10% of our productive, degraded lands to absorb the estimated 6.1 gigatons of carbon dioxide of emissions to make a carbon negative world possible in our life-time. If we open our eyes, increase our understanding of how we can generate carbon negative fuels and scrub fossil fuel emissions of pollutants, we can reverse our historic increase in atmospheric carbon. The question must then be asked: ‘Do we need nuclear power to reduce Global Warming?’ The micro pores and cracks in charcoal provide two important resources for the soil microbial community ‐ a source of entrapped nutrients and ‘safe housing’ for the protection of beneficial bacteria from grazing protozoa. The activated portion attracts and holds nutrients for the microbes, ‘like having food home delivered’. In most situations when charcoal is used in combination with inorganic or organic fertilisers, crop yields increase from improved fertiliser efficiency by reduced nutrient loss from leaching.

The mechanism of carbon isotope fractionation in photosynthesis and carbon dioxide component of the greenhouse effect

Abstract: The relationship between the global climate warming, which is largely induced by increased CO2 atmospheric concentration, and the changes in carbon isotope fractionation in plants was explained in terms of the previously proposed oscillatory mechanism of photosynthesis, according to which CO2 assimilation and photorespiration are two reciprocally coupled oscillating mechanisms controlled by ribulose bisphosphate carboxylase/oxygenase switching. This explanation is confirmed by the changes in carbon isotope fractionation in the annual rings of trees and demonstrates that the light carbon isotope 12C enrichment before 1990s resulted from increased photosynthetic assimilation of CO2. The subsequent sharp 13C enrichment of the tree ring carbon until the present time suggests that the compensatory role of photosynthesis in boreal forests has been lost for the global climate.

Greenhouse gases, global warming and glacier ice melt in Nepal

Abstract: Concentration of greenhouse gases has been found increasing over the past centuries. Carbon dioxide (9-26% greenhouse effect), methane (4-9%), and nitrous oxide (3-6%) are the three principal greenhouse gasses though chloroflourocarbon and halon are also included as greenhouse gasses but are in very small greenhouse effect. These gasses are produced both from natural process and anthropogenic activities .Increase of these greenhouse gasses from nature in the atmosphere is mainly from the decomposition of organic matter, nitrification and denitrification of nitrogen including respiration by the plants. Anthropogenic production of carbon dioxide is from burning of fossil fuel whereas for methane livestock and paddy cultivation. Agricultural activities mainly use of mineral fertilizer is responsible for nitrous oxide emission. Increase of these gasses in atmosphere increases temperature that further accelerates evaporation of moisture from the earth’s surface. Increase in water vapor in the atmosphere will further aggravate temperature rise. This increase in atmospheric temperature has direct effect in the melting of glacier ice in Nepalese Himalaya. Melting of ice and increases water volume in the glacier fed rivers and glacier lakes. Rise in water volume beyond its capacity the glacial lakes bursts releasing millions of cubit meters of water and takes million of lives and properties downstream. If this continues there will be no more ice left in the Himalaya and in the long run all the rivers of Nepal will go dry and country will face serious water shortage for drinking, irrigation and other purposes. The Journal of AGRICULTURE AND ENVIRONMENT Vol. 8, 2007, pp. 1-7

Post-fire vegetation phenology in Siberian burn scars

Abstract: Boreal forests comprise one third of global forested area and are the largest terrestrial carbon store. Forest fires are the regions most dynamic disturbance factor, occurring mainly in Siberia, Russian Far East, Canada and Alaska, and these fires represent a globally important release of terrestrial carbon to the atmosphere, via the burning of vegetation and organic soils. Currently the boreal region is believed to be a net carbon sink, but climate change predictions indicate significant boreal warming, with consequent increases in fire activity and carbon release. Ultimately, the boreal zone may become a net carbon source through forest fires and increased soil decomposition, and there is evidence that the Canadian forest may have already made this transition. Critical to estimating both direct and longer-term fire-related perturbations to boreal carbon storage is knowledge of fire extent, intensity and/or type, which has a strong control on forest fire "damage", the fraction of available fuel combusted, and patterns of post-fire re-growth. These variables are currently derived from model-based assessment of often-uncertain accuracy, introducing large uncertainties to current carbon flux calculations. The post-fire re-growth process is of great importance since whilst fire releases carbon into the atmosphere, carbon sequestration through post-fire regeneration of plants and woody vegetation may help to reduce the amounts of carbon in the atmosphere. Observational data, such as vegetation indices, biophysical vegetation parameters, burnt area and fire radiative power, derived from satellite measurements are exploited to investigate post-fire regeneration and pre and post-fire temporal dynamics in the boreal forest. The relationship between post-fire dynamics and variables such as fire intensity, vegetation cover and climate are investigated. The ultimate aim of the proposed work is to improve insight into the Siberian boreal forest post-fire dynamics, leading to more realistic carbon flux quantification in the boreal biome and subsequently to a better quantitative understanding of the role of boreal forest regeneration in the global atmospheric carbon record.

Probability Distributions for Carbon Emissions and Atmospheric Response: Results and Methods

Abstract: Probability distributions for carbon burning, atmospheric CO2, and global average temperature are produced by time series calibration of models of utility optimization and carbon and heat balance using log-linear production functions. Population growth is used to calibrate a logistically evolving index of development that influences production efficiency. Energy production efficiency also includes a coefficient that decreases linearly with decreasing carbon intensity of energy production. This carbon intensity is a piecewise linear function of fossil carbon depletion. That function is calibrated against historical data and extrapolated by sampling a set of hypotheses about the impact on the carbon intensity of energy production of depleting fluid fossil fuel resources and increasing cumulative carbon emissions. Atmospheric carbon balance is determined by a first order differential equation with carbon use rates and cumulative carbon use as drivers. Atmospheric CO2 is a driver in a similar heat balance. Periodic corrections are included where required to make residuals between data and model results indistinguishable from independently and identically distributed normal distributions according to statistical tests on finite Fourier power spectrum amplitudes and nearest neighbor correlations. Asymptotic approach to a sustainable non-fossil energy production is followed for a global disaggregation into a tropical/developing and temperate/more-developed region. The increase in the uncertainty of global average temperature increases nearly quadratically with the increase in the temperature from the present through the next two centuries.

Numerical Simulation of the Carbon Cycle Over The Tibetan Plateau, China

Abstract: Significant interaction occurs between ecosystem physiological processes and climate. Studying this interaction is beneficial for understanding dynamics of climate change as well as forecasting future climate change. On the Qinghai-Xizang Plateau, the highest plateau in the world, interaction between ecosystem physiological processes and climate affect mid-levels of the atmosphere, so the study of this interaction has a special significance. We use two models, a carbon cycle model (CCM3) and a land surface model (LSM), to simulate ecosystem carbon cycle characteristics over the Tibetan Plateau and its influence on climate. The CO2 flux varies seasonally with ecosystem physiology processes on the Plateau: fluxes are highest in summer and lowest in winter. The seasonal variation of vegetation net CO2 flux shows that vegetation is an atmospheric carbon sink during most of the year, except in winter. This means that vegetation could weaken the greenhouse effect, which is important in terms of global ...